Though the Ginzburg number is an important характеристика of the pair thermal fluctuations, it is not an observable. Then, it is more convenient to employ the fluctuation-shifted critical temperature \(T_c\)  that is a function of \(Gi\) . We can utilize the 3D renormalization group result in the form [1]}
\(\frac{T_c-T_{c0}}{T_c}=\frac{8}{\pi }\sqrt{Gi},\) 
